Lexis meaning ‘word, phrase’ (hence lexicos ‘having to do with words’) and logos

Word-formation activity - the ability of an affix to produce new words, in particular occasional words or nonce-words.
Productive affixes have already served the language and there are a lot of words with them (-er, -ful, -tion).
Active affixes work now, they are used now, they are likely to turn into productive patterns, some of them die out.
Bnum +Sadj >N (one-offs)
The agent suffix -er is to be qualified both as a productive and as an active suffix: on the one hand, the English word-stock possesses hundreds of nouns containing this suffix (e.g. driver, reaper, teacher, speaker, etc.), on the other hand, the suffix -er in the pattern v+-er -> N is freely used to coin an unlimited number of nonce-words denoting active agents (e.g., interrupter, respecter, laugher, breakfaster, etc.).
The adjective suffix -ful is described as a productive but not as an active one, for there are hundreds of adjectives with this suffix (e.g. beautiful, hopeful, useful, etc.), but no new words seem to be built with its help.
For obvious reasons, the noun-suffix -th in terms of this approach is to be regarded both as a non-productive and a non-active one.
Бондарчук:
What can be productive:

1. 
   a means of word formation
   
2. 
   some pattern
   
3. 
   some affix
   

Productivity – the ability to make words it is necessary for the language, this word should be understood by everybody who speaks E.
Activity – number of ws


Means of word formation:
I. main/major/patterned means
1. word derivation (словопроизводство): affixation, conversion (N>V)
2. word composition/compounding (словосложение)
a trouser suit – брючной костюм (a new consept)
II. secondary/minor/non-patterned means
1. sound interchange (man-men, live-life) Historical means
2. stress interchange (‘input – to in’put, ‘progress – to pro’gress)
3. Back-formation (it is still used) – against the logics of the language/ but not against the logics of life.
peas>pea
a babysitter > to baby-sit (logically V > N)
4. Shortening/ abbreviation (lab, exam, Euratom, V-day)
5. Artificial creation of ws (trade marks are made)
nylon
adidas (Adi Dassler)
9) Affixation in contemporary English.